In considering the different forms of external applications, it will
appear that, for their extemporaneous construction, preparation, and
application, the same scientific knowledge, practical skill, and
pathological acumen will be required, as we have already stated to be so
indispensably requisite to enable the physician to prescribe, and the
pharmaceutist to prepare the various remedies intended for internal
administration; although in regard to the former, it may be stated
generally that the prescriber will more frequently be called upon to
exercise that species of knowledge and address which enables the
practitioner to impart a convenient and efficient _consistency_ to his
remedy; for an external application is far more dependent upon this
circumstance for its efficacy, than one intended for internal use.